1108. Finding Average (20)

痛定思痛。 2022-05-28 07:42 143阅读 0赞

The basic task is simple: given N real numbers, you are supposed to calculate their average. But what makes it complicated is that some of the input numbers might not be legal. A "legal" input is a real number in \[-1000, 1000\] and is accurate up to no more than 2 decimal places. When you calculate the average, those illegal numbers must not be counted in.

**Input Specification:**

Each input file contains one test case. For each case, the first line gives a positive integer N (<=100). Then N numbers are given in the next line, separated by one space.

**Output Specification:**

For each illegal input number, print in a line "ERROR: X is not a legal number" where X is the input. Then finally print in a line the result: "The average of K numbers is Y" where K is the number of legal inputs and Y is their average, accurate to 2 decimal places. In case the average cannot be calculated, output "Undefined" instead of Y. In case K is only 1, output "The average of 1 number is Y" instead.

**Sample Input 1:**

7
    5 -3.2 aaa 9999 2.3.4 7.123 2.35

**Sample Output 1:**

ERROR: aaa is not a legal number
    ERROR: 9999 is not a legal number
    ERROR: 2.3.4 is not a legal number
    ERROR: 7.123 is not a legal number
    The average of 3 numbers is 1.38

**Sample Input 2:**

2
    aaa -9999

**Sample Output 2:**

ERROR: aaa is not a legal number
    ERROR: -9999 is not a legal number
    The average of 0 numbers is Undefined

--------------------

题目大意：

代码：

#include<stdio.h>
    #include<stdlib.h>
    #include<string.h>
    int main()
    {
        int i,j,n,m,k,t,l,p,x,num=0,digit=0;
        char str[100];
        double sum=0;
        scanf("%d",&n);
        for(i=0;i<n;i++)
        {
            scanf("%s",str);
            l=strlen(str);
            k=0;
            t=0;
            p=0;
            for(j=0;j<l;j++)
            {
                if(j==0)
                {
                    if(str[j]=='-'||str[j]=='+')
                    {
                        k++;
                    }
                    else if(str[j]=='.'||(str[j]>='0'&&str[j]<='9'))
                    {
                        k++;
                        if(str[j]=='.')
                            {
                                p++;
                                for(x=j;x<l;x++)
                                {
                                    if(str[x]>='0'&&str[x]<='9')
                                    {
                                        t++;
                                        digit++;
                                    }
                                }
                                break;
                            }
                            else
                            {
                                digit++;
                            }
                    }
                }
                else
                {
                    if(str[j]>='0'&&str[j]<='9')
                    {
                        k++;
                        digit++;
                    }
                    else if(str[j]=='.')
                    {
                        p++;
                        k++;
                        for(x=j;x<l;x++)
                                {
                                    if(str[x]>='0'&&str[x]<='9')
                                    {
                                        t++;
                                        digit++;
                                    }
                                }
                                break;
                    }
                }
            }
            if(p<=1&&k+t==l&&digit!=0)
            {
                double tmp=atof(str);
                if(tmp>=-1000&&tmp<=1000&&t<=2)
                {
                    sum=sum+tmp;
                    num++;
                }
                else
                {
                    printf("ERROR: %s is not a legal number\n",str);
                }
            }
            else
            {
                printf("ERROR: %s is not a legal number\n",str);
            }
        }
        if(num==1)
        printf("The average of 1 number is %.2lf\n",sum);
        else if(num>1)
        printf("The average of %d numbers is %.2lf\n",num,sum/num);
        else
        printf("The average of 0 numbers is Undefined\n");
        return 0;
    }